The present invention relates to doors and gateways of sectional type.
As is known, with this definition there are commonly referred to doors and gateways intended for closing garages, sheds or the like, formed by panels hinged together to form a folding structure which is raised and lowered vertically for opening and closing thereof, likewise a shutter.
The aforementioned panels are generally made outside of sheet metal and filled inside with heat-insulating materials, such as polyurethane foam, rock wool, polystyrene and the like; there also exist, however, internally empty panels or others which are made with materials different from sheet metal, such as plastics, wood, aluminium and the like, whose structure may differ considerably from that described above.
What is of interest here is the fact that in order to make doors and gateways safe during the opening and closing operations (which may be manual or motorized, depending on the circumstances), it is known to shape the top and bottom edges of the panels forming them, with a convex portion and a concave portion respectively, having matching profile.
In particular, the radius of curvature of these portions coincides substantially with their distance from the axis of the hinges connecting the panels: in this manner there is delimited an interspace of sufficiently small width between the concave and convex portions, so as to prevent during rotation of the panels following opening or closing of the sectional door, a person""s fingers from being accidentally introduced therein.
This shaped configuration of the panels edges has been well-known since a long time and for this reason nearly all the panels of sectional doors are nowadays made according thereto; among the several prior documents attesting this state of the art, it is only mentioned here the European patent No. 326 131 dating back to 1988 and owned by the company Niemetz Torsysteme.
However, if on the one hand the aforementioned configuration is able to achieve advantageous results in terms of safety, on the other hand it may give rise to certain difficulties during installation of the doors with regard to precise alignment of the panels along the vertical direction.
This alignment is important because some important effects depend on it, such as smooth sliding of the doors during closing and opening thereof or their external appearance: it can indeed be understood that if the panels are not properly aligned, the surface of the door appears to an observer as being undulating or in any case not smooth, thereby resulting unaesthetic.
At present, in order to align the panels vertically as required in the closed condition of the doors, two way are mainly followed: using the joining hinges so that one of their arms abuts against the wall of the panels when they lie vertically, or resting the panels endwise, on one another, when the door is closed.
The first solution is illustrated in the Niemetz patent, whereas the second solution is described in two further published prior documents: European patent Nos. 370,324 and 370,376, both in the name of Hxc3x6rmann KG Brockhagen.
The latter relate to panels for sectional doors wherein further to the concave and convex portions, the top and bottom shaped edges are provided with horizontal flat zones for resting the end of the panels when, following the relative rotation about the respective articulating hinges, they are in the vertically aligned condition.
Furthermore, in one case (patent No. 370,376), the edges of the panels are shaped so as to have stepped zones close to the internal wall, where the hinges for joining the panels may be arranged; these zones are also used for resting the end of the panels.
There are however some limitations which make the known panels considered above unsatisfactory from certain points of view.
As regards the type of panel described in the already mentioned Niemetz European patent, it may be noted that the vertical alignment in the sectional doors depends on the hinges connecting the panels, in the sense that their entire weight bears on said hinges: this weight may also be considerable in the case of large-size gateways, so that the hinges must be made with suitable dimensions and therefore the associated costs also increase as a result.
There is also another important aspect, which relates to safety.
The arm of the hinges which abuts against the front wall of the panels when they are in vertical alignment, tends to move away from the wall itself when the panels rotate during opening or closing of the door, with the result that a person could accidentally introduce a finger into this space, with the risk of serious injury.
It is for this reason that the hinges in the Niemetz patent are provided with special lateral covering flanges which prevent any possibility of fingers being introduced into the zone where the hinge arm is situated.
For the same safety reasons, the hinges joining the panels in the first mentioned European patent to Hxc3x6rmann, have curved arms: in this way, in fact, there is no risk of fingers remaining trapped between the arm and the inner wall of the panels, following relative rotation of the latter during closing or opening of the door.
In this case, however, the curved shape of the arm is unable to provide the bearing surface required for correct mutual positioning of the panels along the vertical and therefore this function is obtained by resting them endwise, one on top of the other when the door is in the closed condition.
This resting arrangement of the panels is also envisaged in the other Hxc3x6rmann European patent which differs from the preceding one in that the shaped edges of the panels have stepped zones, which are close to the inner front wall and between which the pivots of the hinges are positioned.
This positioning arrangement, however, does not allow the arms of the hinges to abut against the wall of the panels: this function is therefore obtained by resting the panels endwise in respective flat zones adjacent to the concave and convex portions of their shaped edges.
It can be easily appreciated that the endwise resting of the panels described in the prior documents above, ensures that they do not bear with their whole weight on the joining hinges as instead occurs in the case of the Niemetz patent; as a matter of consequence it is possible to avoid the abovementioned difficulties resulting from the use of strong and hence costly hinges.
However, the abovementioned resting arrangement gives rise to problems concerning the mounting of the sectional doors.
It can indeed be understood that the panels must be joined together in a precise manner to ensure that, at the end of their relative rotation, they assume the vertically aligned condition resting one on the top of the other; this requires small tolerances, both in the design of the panels and assembling thereof.
Furthermore, it can be assumed that in the event of thermal expansions, deformations, cave-in give or plays between the joined panels, small changes in their relative position occur which however may result in significant modifications of their operating condition.
For example, it can be noted that when an upper panel rests endwise on a lower panel at the conclusion of their relative rotation during closing of the sectional door, inevitably the weight of the former is transmitted to the latter through the respective horizontal contact zones; in the long run this may cause wear, deformation or crusching of the zones concerned, such that the panels no longer fit together as they should and therefore their vertical alignment is also adversely affected as a matter of consequence.
In other words it may be stated that the configuration of the panels described in the Hxc3x6rmann patents does not allow to offset their variations with respect to the initial condition, which may arise with time and with use.
The present invention aims at remedying this state of the art: that is to say, it has the object of providing a sectional door with panels suitable to overcome the drawbacks mentioned above in relation to the known ones.
This object is achieved by a door whose features are set out in the claims appended to this description.